click below
click below
Normal Size Small Size show me how
Astronomy Review
Midterm Review Sheet Summarized. Missing some stuff.
Question | Answer |
---|---|
The standard view of the scientific method (6 things) | 1. Observation of nature 2. Detection of patterns or regularities 3. Induction of underlying laws of nature 4. Deductive prediction of new phenomena 5. Experimental test of prediction 6. Generalization and reduction |
• Kuhn’s alternate view of the scientific method (5 things) | 1. Science has 2 phases, normal and crisis 2. Normal science is what happens most, ruled by a paradigm 3. Occasional measurements do not agree with predictions, usually do not overthrow the paradigm 4. When enough contradictions build up, a revolution can |
The role of measurement in science (3 things) | Occasional measurements do not agree with predictions, usually do not overthrow the paradigm. When enough contradictions build up, a revolution can occur. With a new paradigm, science reverts to normal mode, and progress resumes. |
Celestial Sphere | The apparent dome of the sky |
Zenith | The overhead point |
Meridian | from north through zenith to south |
Noon | Sun on meridian |
Right Ascension | longitude |
Decliniation | latitude |
Azimuth | Angle from north through east along horizon toward zenith (Horizon Coordinate) |
Which coordinates change with time due to rotation of earth? | Horizon Coordinates |
Motions in the sky of stars(3 things) | Diurnal (24 hour) motion E to W, Circumpolar stars never set, Except at equator, only part of sky visible |
Umbra | full shadow (darkest part) |
Penumbra | partial shadow |
Lunar Eclipse | Earth’s shadow falls on the moon |
Solar Eclipse | Moon’s shadown falls on earth |
Gibbous phases of the moon | 3/4 of moon |
Waxing phases | light part of moon on right |
Waning phases | part of moon on left |
Saros Cycle | 18 year 11 day period between eclipses |
Pythagoras(4 beliefs) | Believed in Number, Harmony, Order, and Geometry |
Aristarchus (4 things) | Aristarchus’ model explains retrograde motion naturally, and has no counter-earth. 6 Rings, moon revolves around earth. Calculated the distance of the moon relative to distance of earth and size of moon and sun |
Geocentric tradition | Caused the decline of real science (Plato) real world vs visual world. Elevation of authority, perfect spheres, |
Plato (3 things) | Began the decline of greek science, Believed in Visible world of "perception" and real world of "perfection". Circle is a perfect figure |
Aristotle (3 things) | 4 elements: earth, water, fire, air. Natural places: Earth lowest, fire highest. Argued against heliocentric theory |
Hipparchus (7 things) | Built observatory on Rhodes. Catalogued ~850 star positions and brightness. Invented modern magnitude system. Rediscovered Precession. Deferent – basic circular orbit. Epicycle - Smaller orbit on a planet. Eccentric - Displacement of the earth from center |
Ptolemy (7 things) | Used Hippachus’ models. equant- a point opposite from the eccentric, at the same distance from the center. Planet’s epicycles move at a variable speed. Speed appears constant as seen from equant. 40 circles in model. Most successful theoryever,accurateish |
Indian Astronomy (5 things) | Improved many observing techniques and made careful observations. Improved the way planetary positions were calculated. The first to build observatories like their modern counterparts Observed to verify works of astronomers, not to challenge Used Pt. Aris |
Chinese Astronomy (4 things) | o Recorded observations of eclipses since the 13th century bc o Recorded meteor showers, lunar and solar eclipses for hundreds of years o Observation of Haley’s comet in 466 bc o Discovered accurately the length of year, precision,predicted eclipses |
MesoAmerican Astronomy (4 Things) | o Built observatories 6000 years agoo Astronomers used to keep track of yearly cycles of agriculture o Had 12 constellations used today to mark annual passage of the sun with respect to stars. o Brighter stars given names to distinguish |
Egyptian Astronomy (3 things) | o Originated dividing circle 360 degrees with minute and second divisions in the circle o First to use leap month o First to use leap month |
Copernicus (4 things plus equation) | Has circular orbits and uniform circular motion Added small epicycles to account for variability (1/Synodic period planet M) = (1/Sidereal period plant E) – (1/Sidereal planet M) As complicated but no more accurate than ptolemy’s model Prob with parallax |
Tycho (4 things) | “difficult” personality Showed a nova had no parallax, a blow to aristotlean physics Had largest most accurate instruments Sun, moon, revolved around earth |
Kepler (3 things) | “Harmony of spheres” spheres inscribed in regular solids (cubes, tetrahedrons, etc) Initial model of circles rejected because data wasn’t accurate enough. Created a cause for motion of planets. Sugg. a force came from sun (magnetism) + decreased w/distanc |
Keplers 3 laws of Planetary Motion | 1st law: Orbits are ellipses with sun at focus (overthrowing circles) 2nd law: orbital speed varies, planets move fastest when closest to the sun 3rd law: Period^2 = AU^3 |
Galileo (5 things) | Concept of inertiaConcept of forceFalling objects move at constant accelerationObserved craters on the moon, 4 moons of Jupiter, Milky way into stars, phases of venus, and saw Neptune but didn’t recognize as a planet.For writing a book that challenged and |
Newtons 3 laws of dynamics | 1. Inertia2. Force = Mass * Acceleration3. for every action, there is an equal and opposite reaction |
Gravity Equation | Force of Gravity = G(mM/d^2) |
nature of light | o light travels at, well, the speed of light and has wavelength and frequency |
blackbody radiation | o The amount and type of electromagnetic radiation they emit is directly related to their temperature. Black bodies below around 700 K (430 °C) produce very little radiation at visible wavelengths and appear black (hence the name). Black bodies above this |
Wien’s Law | o Wavelength (cm)* Temperature = .28 o For Wavelength and Temperature If you raise one number, the other must go decrease |
Stefan-Boltzmann Law | The energy from an star (Flux) = sigma * T4 |
Reflecting telescopes | use a mirror. They are relatively lightweight, therefore can get pretty large (aka large aperture). They have shorter focal lengths than refracting telescopes |
Refracting telescopes | use a lens. Lenses are heavy and bulky and can only get so big (aka limited aperture). Refracting telescopes however provide sharper, more detailed images |
space telescopes why? | o Putting a scope in space is a good idea cuz u are above the atmosphere that absorbs a lot of different electromagnetic radiation (light, x-rays, gamma rays, uv rays) |
Radio telescopes | o radio telescopes can be on earth cuz the atmosphere doesnt absorb radio waves that much |
Formation of the solar system general characteristics (1-5) | 1. All planetary orbits lie in a single ecliptic plane 2. Sun’s rotation equator is in ecliptic 3. Planetary orbits are nearly circular4. Planetary revolution is W to E5. Sun and 6 of 8 planets rotate prograde with small axis tilts |
Formation of the solar system general characteristics (6-10) | 6. Planetary distances obey Titus-Bode Rule – no known basis in physics7. Most rotation periods 5-10 hours, unless slowed by tides8. Composition varies with distance from sun:9. Meteorite compositions difer from planets10. Cometary orbits ub Oort cloud |
Formation of the solar system general characteristics (11-12) | 11. Planet-satilite systems resemble solar system 12. Planets have much more angular momentum than the sun |
Exoplanets 2 discovery methods | 1direct – imaging planets around other stars 2. o indirect – effects of planets on their stars (position wobble [astronomy], velocity variations [spectroscopy], eclipses [photometry]) |